The present invention relates to flavors and fragrances, and in particular to methods for providing flavorgenic alcohols and aldehydes using plant tissue.
Leaf alcohol (i.e., cis-3-hexen-1-ol) and leaf aldehyde (i.e., trans-2-hexenal) are present in a wide variety of fresh leaves, vegetables and fruits. These compounds are responsible for a so-called "green odor", "green aroma", "fresh note" or "green note". Related compounds present in many plants include trans-2-hexenol, cis-2-hexenol, trans-3-hexenol, 1-hexanol, 1-hexanal and cis-3-hexenal. Green note compounds and uses thereof are set forth by Morris, Perfumer & Flavorist, Vol. 6, No. 1 (1981) and Clark, Perfumer & Flavorist, Vol. 15 (1990). Green note compounds exhibit organoleptic characteristics which can be characterized as fresh or grassy in nature. Such compounds can be used to sharpen and enhance flavored products, such as those products having fruit flavors.
Green note compounds have been isolated from plants or chemically synthesized, as reported by Bedoukian, Amer. Perf. Vol. 78, p. 31 (1963) and U.S. Pat. No. 3,839,457 to Jouffret. Green note compounds are present in plant essential oils (e.g., sage, citrus and mint), and have been obtained by steam distillation of plant material followed by fractional distillation or "topping" techniques. Green note compounds also have been biosynthetically produced, as reported by Muller et al, Adv. Flav. Res. Tech. Symposium (1993); Hatanaka el al, Phytochem., Vol. 17, p. 869 (1978); Hatanaka, Bull. Inst. Chem. Res., Kyoto Univ., Vol. 61, p. 180 (1983); Lumen et al., J.Food Sci., Vol. 43, p. 698 (1978); Hatanaka et al., Phytochem., Vol. 17, p. 869 (1978); Sekiya et al., Phytochem., Vol. 23, p. 2439 (1984); Hatanaka et al., ACS Symposium Biogeneration of Aromas (1985); French Patent Application No. 2,652,587; U.S. Pat. No. 4,769,243 to Kanisawa et al and U.S. Pat. No. 4,806,379 to Goers et al; and WO 93/24,644. The biosynthetic reaction involving the unsaturated C-6 hydroperoxydismutation of linolenic acid is carried out using a series of enzymatic steps. In particular, lipoxygenase forms a hydroperoxide moiety at a double bond of linolenic acid. The hydroperoxide lyase cleaves the hydroperoxide to produce a C-6 unsaturated aldehyde, in particular, cis-3-hexen-1-al. Then, aldehyde isomerase, when present in the plant material and under certain conditions, catalyzes the formation of a trans-2-hexenal from the cis-3-hexen-1-al. Cis-3-hexen-1-ol and other green note alcohols are formed by the action of alcohol dehydrogenase, which reduces the aldehydes to alcohols.
It would be highly desirable to provide an efficient and effective method for biosynthetically producing natural green note compounds, such as cis-3-hexen-1-ol. In particular, it would be highly desirable to provide green note compounds, such as shortchain saturated and unsaturated alcohols and aldehydes, which result from the enzymatic oxidation of a fatty acid substrate.